Tach still doesn't work...or maybe the Rectifier doesn't...? NOW FIXED!

[bunker108]

I can't get this old Airguide tach to work. It reads nothing wired to the control box and pegs out at 7K RPM with the brown wire switched to the yellow wire coneection.

Is it safe to assume I need a recitifier? Where would be a good place to source one?

Thanks!

 

[Barnacle_Bill]

Re: Tach still doesn't work...or maybe the Rectifier doesn't...?

Re: Tach still doesn't work...or maybe the Rectifier doesn't...?

What motor? You can test the rectifier.

 

[bunker108]

Re: Tach still doesn't work...or maybe the Rectifier doesn't...?

Re: Tach still doesn't work...or maybe the Rectifier doesn't...?

opps..forgot to mention that vital piece of info...

it is a 72 Merc 1150 on a 73 Starcraft.

 

[bunker108]

Re: Tach still doesn't work...or maybe the Rectifier doesn't...?

Re: Tach still doesn't work...or maybe the Rectifier doesn't...?

I replaced the rectifier today...and the tach will only move if I tap it. So I decided that the tach must be bad, the volt meter wasn't good either so I replaced that and it works now. Anyway I bought a Teleflex Tach on sale at my local marine store. I wired it all up, set it to 6p and nothing...so I switched the brown wire on the swichbox to one of the stator wires at the rectifier, still nothing. I am using +12v from the harness and ground from the NBB. Which is the signal wire? I tried both extra wires from the tach harness with no luck. I also ran a jumper wire from the stator wire connection to the signal terminal on the back of the tach and still nothing. I am our of ideas here so any help would be much appreciated.

Thanks!

 

[Gomer50]

Re: Tach still doesn't work...or maybe the Rectifier doesn't...?

Re: Tach still doesn't work...or maybe the Rectifier doesn't...?

Black is ground- white is 12 volts- and brown is the signal wire.Try moving the brown to the other stator wire on the rectifier.Make sure you have 12 volts and the tach is grounded.Hopefully your recitifier isnt blown.I had to run a seperate wire back to the recitifier because somewhere it had a short in the harness.

 

[bunker108]

Re: Tach still doesn't work...or maybe the Rectifier doesn't...?UPDATE

Re: Tach still doesn't work...or maybe the Rectifier doesn't...?UPDATE

Did some more trouble shooting and no luck.

I have 11.72 volts at the ign wire and good ground. I also have .298v at the snd wire.

I have 11.72 at + on rectifier and .307 and .298v at the other terminals. Do these numbers mean anything?

I am on my way to get some new batteries as these ones are weak. Not sure if the system is charging or not because my readings were just shy of 12v at idle and just above. I didn't want to rev it too much on ear muffs.

The tach does slowly zero when the ign is turned on.

 

[bunker108]

Re: Tach still doesn't work...or maybe the Rectifier doesn't...?UPDATE

Re: Tach still doesn't work...or maybe the Rectifier doesn't...?UPDATE

Ok I bought new batteries and now the tach works...who would have thunk it?

Ok now for new problems...I will start a new thread!